The economy added only about 100,000 private sector jobs last month - far fewer than had been expected.

And as NPR's Wendy Kaufman reports, a close reading of the numbers reveals that many of those jobs are low wage.

WENDY KAUFMAN, BYLINE: Some of the nation's job growth has been in places like this - a suburban mall near Seattle. While many shoppers aren't spending like they did before the economic crash, they are buying more than they did a couple of years ago.

An analysis by Mark Vitner, a senior economist at Wells Fargo, shows that about 40 percent of last month's job growth - and indeed all job growth since early 2010 - has occurred in just four industries: the retail trade; leisure and hospitality - that includes restaurants; home health care; and temporary staffing.

MARK VITNER: And when you weight the wages, it works out to about $15 an hour.

KAUFMAN: Far less than the average private sector wage of about $23.50 an hour. What's more, many of the new jobs are part-time and have few if any benefits. The result says Vitner is pretty obvious.

VITNER: The composition of job growth being so heavily weighted toward low wage jobs explains a lot of why it's been so hard for us to break out of this 2 percent growth holding pattern that we've been in.

KAUFMAN: He goes on to say a lot of Americans aren't working in the jobs they'd like to have and many of these low wage workers are not out there spending like they otherwise would. It's a vicious cycle because consumer spending makes up the bulk of the U.S. economy.